There is currently available a shearing device for cutting boards of particulate material and the like, which attaches to the chuck end of a drill. Two fixed outer cutting blades are attached to a body with a third movable centre cutting blade adapted to pivot in a plane centrally between the outer cutting blades, such that the device performs a scissor cutting action with the centre blade moving relative to the outer cutting blades. The centre cutting blade is pivotally driven by an eccentric cam driving cam following surfaces on arms extending from an end of the centre cutting blade. The eccentric cam is fastened to, and driven by, a drill attached to the body.
The cutting blades are positioned closely together such that there is minimal clearance between the cutting edges of the blades as the centre cutting blade pivots. The cutting edges are straight or substantially straight and manufactured from steel.
The prior art device is capable of cutting through material only up to about 4 mm thick and produces dust from the material when cutting, which can be a serious respiratory hazard. The cutting edges and cam following surfaces are also subject to high wear rates.